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  5. Ratio and Proportion

6th Class Mathematics Ratio and Proportion Question Bank Ratio, Proportion & Unitary Method

  • question_answer
    21 binders of GOF can bind 1400 books in 15 days. How many binders will be required to bind 800 books in 20 days?

    A)  7                                

    B)  9

    C)  12                  

    D)  14

    Correct Answer: B

    Solution :

    Let the required number of binders be\[x\]. Less books, less binders (Direct proportion) More days, less binders (Indirect Proportion) \[\left. \begin{align}   & \text{Books}\,\,\,\text{1400:800} \\  & \text{Days}\,\,\,\,\,\text{20:15} \\ \end{align} \right\}\text{:}\,\,\,\text{:}\,\,\,\,\,\text{21:x}\] \[\therefore \]\[1400\times 20\times x=800\times 15\times 21\] \[\Leftrightarrow \]\[x=\left( \frac{800\times 15\times 21}{1400\times 20} \right)=9\]


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